How to compare landing-page performance by device in Google Analytics
Google Analytics can tell you which landing pages work well and which devices people use to visit your site. What it won't do is automatically flag up when your mobile visitors are having a worse time than everyone else. That bit requires some poking about in the interface and a reasonable understanding of what you're looking at.
The good news is that once you know where to look, comparing landing page performance by device becomes straightforward enough. The less good news is that a difference in the numbers doesn't automatically mean your mobile site is rubbish – it might just mean mobile users behave differently, or that you're attracting different audiences on different devices. Still, spotting a gap is the first step to working out what's actually going on.
Why this matters in the first place
Most websites now see more mobile traffic than desktop traffic, which is hardly news. What is worth paying attention to is whether those mobile visitors are actually doing what you want them to do. If your desktop users convert beautifully but mobile visitors bounce like rubber balls, that's worth investigating. It might be a clunky form, a carousel that won't swipe, or just text that's impossible to read without zooming in like you're examining a postage stamp.
Landing pages are particularly useful to examine because they're where people arrive. If someone searches for something, clicks your result, and immediately leaves, either the page didn't match what they expected or the experience put them off. Knowing which pages do this and on which devices helps you work out what needs attention first.
Where the data lives in GA4
GA4 doesn't have one magic report that shows landing page performance split by device type with a big red warning light when something's wrong. Instead, you need to combine a couple of dimensions and do a bit of manual comparison. The landing page report lives under Reports, then Engagement, then Landing page. This gives you a list of pages where sessions started, along with metrics like users, sessions, engagement rate, and conversions (or "key events" as GA4 now insists on calling them).
On its own, this tells you which landing pages get traffic and which perform well overall. To see how devices factor in, you need to add a secondary dimension. Click the plus icon next to where it says "Landing page + query string" at the top of the data table, then search for "Device category". This splits each landing page row into separate entries for desktop, mobile, and tablet.
Now you can see the same landing page's performance across different device types. A page might show a healthy engagement rate on desktop but a dismal one on mobile. Or conversions might be strong across the board except on tablets, which nobody seems to finish anything on. These patterns are what you're looking for.
Which metrics actually tell you something useful
Engagement rate is a decent starting point. GA4 defines an engaged session as one lasting longer than 10 seconds, having a conversion event, or involving two or more page views. It's not perfect, but it's better than the old bounce rate for working out whether people found what they came for. A low engagement rate on mobile suggests people are leaving quickly, which might indicate a problem with the page or just that mobile searchers are more impatient.
Key events (conversions) are obviously important if your site is meant to generate leads, sales, or sign-ups. If desktop users convert at 5% but mobile users at 1%, that's a substantial gap worth investigating. Before you blame the mobile experience entirely, though, consider whether mobile users are just browsing while desktop users are more ready to commit. The behaviour might be different for legitimate reasons.
Sessions and users tell you about volume. A landing page might perform beautifully on mobile but barely get any mobile traffic, in which case optimising it further probably isn't your priority. Conversely, a page with thousands of mobile sessions and terrible engagement is screaming for attention.
Average engagement time can be revealing too, though take it with a pinch of salt. People don't necessarily read slowly because they're engaged – they might be scrolling around trying to find what they actually want. Still, if desktop users spend two minutes on a page while mobile users spend fifteen seconds, something's clearly different about the experience.
What to do when you spot a gap
Finding a performance difference by device is a clue, not a diagnosis. Before you start ripping apart your mobile templates, it's worth checking a few other things. Look at where the traffic is coming from – are mobile users arriving from different sources than desktop users? Different traffic sources often have different intent and behaviour patterns.
Check the page itself on an actual mobile device. Load it on a phone with a mediocre connection and see what happens. Does it take ages to load? Do buttons work? Can you actually read the text without squinting? Is there an interstitial pop-up that's impossible to close on a small screen? Sometimes the problem is immediately obvious once you look at it the way most of your visitors do.
If the mobile experience looks fine and loads quickly, the issue might be with the content or the offer itself rather than the technical implementation. Maybe the page is aimed at something people research on mobile but complete on desktop. Or perhaps mobile visitors are earlier in their journey and not ready to convert yet. Understanding the context matters as much as the numbers.
Making the comparison more sophisticated
Once you're comfortable with the basic comparison, you can layer on more dimensions to get even more specific. Adding "Session source/medium" alongside device category shows whether traffic from Google on mobile behaves differently than traffic from social media on mobile. Adding "Country" might reveal that mobile performance is fine in the UK but terrible in markets where 3G connections are more common.
You can also create a custom exploration if you want more flexibility than the standard reports allow. Explorations let you drag and drop dimensions and metrics to build exactly the view you need. For comparing landing pages by device with specific segment filters applied, it's considerably more powerful than the standard reports, though the interface takes a bit of getting used to.
The bit where we don't oversell things
If you've made it this far and found this article genuinely useful rather than just mildly irritating, we've written quite a lot more about search and analytics. These should get you started if you're in the mood for more:
Google Search Console for Beginners: Opening the Bonnet on What It Is (And Why You Need It)
What your bounce rate actually measures (and why a high number isn't always bad)
Why your 'Average position' in Search Console doesn't mean what you think it means
We write about search and analytics because it's part of what we do when we build websites for clients. Getting a site built is one thing; making sure it actually works and knowing whether it's performing is another. When we build your website, the analytics setup is included as standard because a website without analytics is like a shop with no idea how many people came in or what they looked at.
We also offer an ongoing management service for clients who'd rather not spend their time learning the finer points of GA4 (which is completely understandable). We handle the monitoring, spot the problems, and let you know what actually needs your attention rather than drowning you in reports full of numbers that may or may not mean anything. It means you can focus on running your business while someone competent keeps an eye on whether your website is pulling its weight.
You can find out more about all of this here:
Shall we build you something good?
If you'd like us to build you a website that works properly on all devices and comes with analytics that actually tell you useful things, get in touch. We'll have a proper conversation about what you need rather than immediately trying to sell you a package with a name like "Premium Business Plus". No obligation, just a chat about whether we're a good fit for what you're trying to achieve.
How do I see landing page performance by device in GA4?
Go to Reports > Engagement > Landing page, then add 'Device category' as a secondary dimension by clicking the plus icon next to 'Landing page + query string'. This splits each landing page into separate rows for desktop, mobile, and tablet so you can compare performance side by side.
What does it mean if my mobile engagement rate is lower than desktop?
It depends on the gap and the context. A lower mobile engagement rate might indicate a technical problem like slow loading or clunky forms, but it could also mean mobile users are just browsing while desktop users are more ready to commit. Check the actual mobile experience first, then consider whether different devices attract users at different stages of their journey.
Why would mobile and desktop users behave differently on the same page?
Different devices often attract users with different intent or at different stages of their journey. Mobile users might be researching while out and about, whereas desktop users might be more ready to complete purchases or fill out forms. Traffic sources can also differ by device, bringing audiences with completely different expectations.